stare



E. TQSTARR,

DENTAL' DRILL.

(No Model.)

JVT/'EJVTOR im' zwar, By Inf- .dtfurual @um @Le N. PlTERs Pvwknuhogmpher, wnhingmn, D. C.

UNITED STATES PATENT EEICE.

ELI T. s'rAEE, oE PHILADELPHIA, PA., Assie-Noa To JAMEs W. WHITE, JAMEs CLARENCE WHITE, AND E. M. LEWIs, TEUsTEEs, on sAME PLAGE.

DENTALl DRILL.

SPECIFICATION forming part of ILetters: Patent No. 276,921, dated May 1, 1883.

` -Application tiled April 30, 1881. (No model.)

of Pennsylvania, have invented certain nevvr and usefulImprovements in Dental-Engine Hand-Pieces and Operating-Tools, of which the following is a specification.

My present invention relates to an improved Y hand-piece ot the type shown in my Letters Patent Nos. 233,7()Saiid233,709, of 0ctoher26, 1880. Theohjects of, my present invention are, first, to improve the construction of the handpiece, so that wear of the spindle-chuck and 4i 5 of its bearingsmay be readily compensated for, and unsteady'inovemeiits or Wabhling of said chuck in its hearings he prevented without interfering with the free rotation of the chuck upon its longitudinal axis; secondly, to

o improve the organization of the tool-locking devices of the spindle-chuck, so as to permit rapid and easy insertion ofthe operating-tools in and their ready removal from the socket of the chuck, while firmly and securely locking said tools in saidsoeket as against endivise movement when at Work; and, thirdly, to iinprove the construction of the shanks of the operatingtools, so that they may be accurate] y -centered in the chuck-socket, and so that Wear 3o .of the tool-Shanks and ofthe chuck-socket may be compensated, in vorder to prevent all unsteady motion or lateral vibration of the tools in the socket of the chuck While at Work, Wherehy dental operations may be performed With greater ease, nicety, and skill than heretofore,

with a considerable saving ot' time to the operator and the avoidance of noise disagreeable to the patient.

' The subject-matter claimed is recited at the 4o close of the specication.

The accompanyingV drawings represent my present improvements as organized in the best` view, partly in section, of a portion of the spindle-chuck, the operating-tool, and the toollocking devices and their controlling-sleeve, the scale being still larger than that of Figs.

FigS is a 1 and'?. Fig. 4 is a cross-section through the chuck and tool-shankon the line 4 4 of Fig. 3. Fig. 5 is a view of the improved tool on a largely-magnified scale. Fig. 6 is a view of a 55 cylindrical tool-shankA havin g a plain liattened driving end; and Figs. 7 and 8 are modifications ofthe tool shown in Figs. 2 and 5.

The hand-piece casing A is shown inthis example as constructed ot' four tubular see- 6o tions-that is to say, it is shown as consisting, first, of a handle-section, a, having preferably a detachable hard-metal nose, Which gives bearing to and envelops the front end ot the spindle-chuck or tool-holder` B; second,ot` a section, a', to which the handle-section er is detachahly connected-hy screw-threads pret'- erably-said sect-ion c' affording the hearing for the rear end of the spindle-chuck; third,` of a section, n2, which is detaehahly connected 7o with the huttend of section by screwthreads preferably-so as to permit disconnection of said sections a' a2, to permit access to the adjustable cone-collar b on the rear end of the spindle-chuck B; and,fourth, ot' a shank- 75 section, n3, which is connected with the section a2 by a swivel-joint, a4, of Well known construction, in order to permitthe handle-section, which is grasped by the hand, (beiiigordinarily held centrally of the lingers and thninbi of the 8o operator,` somewhat after the fashion of holding a pen or pencil,)`to be turned relatively to said shank-sectioii around the spindle-chuck, so as to conform to the turning movements of the operators hand in manipulating the tool.

In order to prevent accidental unscrewing of the handle-section ay or the casing-section c2 i from the intermediate casing-section, a', while permitting their ready disconnection when desircd, I employ a slide, C, fitting a longitudi- 9o nal groove, c, in the exterior of the section d', and also fitting corrcsl'ioiiding grooves or recesses in the flanges e c2, respectively, ot' the hand le-section a and casing-section a?, as clearly shown in Figs. 1 and 2. rlhis slide C iis slot- 95 ted longitudinally for the passage of a screw, forexainple, which holds the slide in the groove in casing-section a', While permitting it to move endwise to a limited extent. When the slide is in the position shown in Figs. 1 andi). me it will he obvious that neither the handle-section n iior the casing-section a? can be unscrewed from the casing-section a', while if moved endwise to carry it ont of the groove of either said handle-section a or said section a2 the disconnection of the free section may be readily accomplished. The slide is provided on its upper face with cross ribs or grooves, so that the thumb-nail may be applied to readily move it. The shank-section a3 of the casing A is connected, in the usual way, with the outer or free end of a exible sheath or tube, while the butt-end of the spindle-chuck or toolholder B is connected, in the usual way', with the outer or free end of arflexible drivin g-shaft or poWer-conveyer enveloped by the beforelmentioned sheath or tube, the inner end of said flexible shaft being connected with a driven spindle or shaft of the engine to receive motion therefrom, so as to impart a rapid revolving motion to the spindle-chuck in its bearing in the hand-piece casing. The said flexible enveloping sheath or tube andsaid flexible shaft or power-conveyer may be similar to those in common use, or to those shown in Letters Patent heretofore granted to me September 2,1879, and November 25, 1879, numbered respectively2l9,820 and 222,093; but as neither said sheath and shaft nor the particular organization of engine employed constitute the subject-matter claimed by me herein, it is unnecessary to illustrate them in the drawings or describe them herein in detail.

The front end of the spindle-chuck Bis socketed for the reception of the shanks of the operating-tools, as usual, and has its bearing in the nose of the handle-section a, of the casing A, while the rear end of the chuck is extended through the section a', so' as to have its rear bearing therein. A collar or ring, b, having a tapering or cone end, is screwed upon a male screw, b', formed upon the rear end of the spindle-chuck, so as to be adjustable', and so as to fit with its cone end in a correspondingly-formed seat in the butt-end of the casing-section a, the`collar being locked to the spindle, when properly adjusted, by a setscrew, b2, as clearly shown in Fig. 2. Said adjustable cone-collar b constitutes the pulljournal ofthe spindle-chuck-that is to say, it constitutes a surface or journal which prevents the endwise forward movement of the chuck in the casing when apulling or draw cutis being made with the operating-tool.

A friction-collar, b3, externally tapered at its rear end, is fitted upon the spindle-chuck, s o as to t with its tapered or conical butt-end into a corresponding seat in the frontend of the'casing-section a. The friction-collar b3 is held to its seat in the casing-section a by a collar, b4, fitting' the spindle, and having a tapering or conical butt-end which lits a corresponding seat in the front end of said friction-collar, the cone-collar b4 being locked to the spindle by a set-screw, for example, as clearly shown in Fig.` 2. Said cone-collar b4 constitutes the thrustjournal or surface ofthe chuckthat is to say, it constitutes ajournalor surface which prevents the endwise backward or inward movement of the chuck in the casing when a pushing or thrust out is being made with the operating-tool.

It will be seen that no endwise movement of the spindle-chuck can take placein the casing, while as wear occurs between the parts it can be readily taken up or compensated for by the adjustment of the cone-collar b, above described.

The several collars b b3 b4 are made detachable, so as to be readily renewed when required.

The conical supplemental friction-collar b3 is preferably made of hard metal, as also the cone-collars b b4. Said friction-collar protects the casing-section a from wear due to the thrust of the chuck, inasmuch as it is prevented from turning with the chuck by the friction between its externally-tapered or conical buttend and said case-section,and thereby receives the thrust and wear instead of the case-section. Y

By the employment of the loose friction-collar not only is wear of the casing-section a prevented, but the ready substitution of a new thrust-bearing or friction-collar in place of one which has become too much worn is permitted. This construction avoids the necessity, in order to prevent Wear of the casing-section which is to sustainthe thrust of the chuck, of a xed steel facing fastened in and forming an' integral part of said section, as shown in the patent of Cushing, No. 218,239, of August 5, 1879, for instance.

It will be observed that a chamber, cl, is formed between the front end ot' the spindlechuck and the end of the casing-nose, through which the tool-shank is inserted on its way to the chuck-socket, and this is for the purpose of arresting the passage into the front bearin g and chuck-socket of saliva, grit, Sto., taken up by the revolution of the tool; and, furthermore, to prevent the exudation of oilfrom the front bearin g to soil thefingers of the operator or face of the patient; but as this is the invention of Dr. Phillips, heretofore patentedl to him, it of course is not claimed as ofmy invention.

The shank ofthe operating-tool E, adapted to my improved hand-piece, is a straight cylindrical shank having an annular groove, e, and in rear thereof provided with a tapered surface, e', to lit a corresponding surface in the chuck-socket, so as to center the tool in the socket and make it t firmly therein. The butt-end of the shank is cut away or flattened, as at e2, so as to have a hat or beveled driving-surface, which is acted upon by a suitable lug, pin, or actuator, d', in the socket of the chuck. rlhe front end of the tool terminates in the usual operating-point, which may be in the form ot' a cutting-burr, drill, slotter, disk, or other working-point.

The groove c in the tool-shank is preferably a concave one, and is for the engagement of IOO IIO

the devices which lock the shank in the socket ofthe chuck as against endwise movement.

y This groove is peculiar, in that it forms a notch or recess for the engagement of the tool-locking devices, so formed that its rear wall, e, is`

ing devicesthe'tool will be moved or wedged` backward by reason of its inclined wall, and the tapered surface e crowded tirmly into its corresponding seat in the chuck-socket.

In practice I contemplate constructing the operating-tool either in a single piece or in sections, as shownin Fig. 5, one section consisting ot' thepeculiarly-formed cylindrical shank, and the other of the operating-point',with a short shank or extension iitting a socket in the front end of the cylindrical portion, the

two sections of the tool being rigidly united,`

for instance, by a transverse pin or rivet, or by solder.

In Figs. 7 and 8 ot the drawings I have shown a modification ofthe tool depicted in Figs. 2 and 5, in that the tapering surface e is formed at the extreme end ot' the toolshank, instead ot'just in front ot' its tlattened drivingsurface e2.

The cylindrical portion of the tool-shank tits snugly the opening in the nose of the handpiece, through which the shank is passed on its way to the chuck-socket, while, as before stated, the tapered surface e of the shank ts a corresponding surface in the chuck-socket. The tool is positively driven, when inserted in the socket of the chuck, by the pin or lug d', crossing or extending into said socket and engaging the flattened driving-surface ofthe tool, while' the tool is locked from endwise movement or withdrawal bylthe tool-locking devices, consisting of three'plate-springs, F F F, arranged around the'chuck at equal distances apart, as shown in Fig. 4. The locking-springs lie in longitudinal recesses in the chuck, and are secured therein, at their rear-ends, by any suitable arrangement. Said springs are so constructed as to have a tendency at their front ends to move outward or laterally when not compressed by a sleeve or thimble, G, surrounding the chuck, and movable endwise thereon.

The front laterally-movable ends ofthe three locking-springs 'are each provided with a pret'- erably tapered, inclined, or cam lug, f, projecting into a lateral opening intersecting the bore or socket ot' the chuck, and each lug comes in contact, when compressed, with the inclined wall ot' the locking groove or notch in the tool-shank, and thereby, as the lugs are 'forced down into the groove, forces the tool backward and crowds or draws its tapered surface firmly into its seat in the chucksocket, whereby the tool is not only tirmlyloeked from withdrawal, but is also accurately centered in the socket and prevented l'rom wabbling or rattling therein. Any wear` that may occur between the tool and the socket is also compensated for, and the tool always driven firmly and without rattling or loose movement.

. I have found that the simplest way offorming the inclined locking groove or notch e in the tool-shank is to make the groove concave, as shown; and I have also found that the three springs, arranged around the chuck atequal dis tances apart,'are more advantageousthantwo springs, such as shown in my aforesaid Patent No. 233,709. Instead of forming the lockinggroove e with an inclined rea-r wall, the groove may be a plain annular one, in which ease it will be found that the action ot' theeam-lugs f i ot" the springs F on the edge ot' the rear wall ofthe groovewill cam or crowd the tool into the socket. Y The sleeve G is thrust forward to compress the lugended tool-locking. springs by means of a coiled spring, H, also surrounding the tool-holder or chuck, and compressed between the fixed collar btat rear and the'annular shoulder formed by the butt-end ot' the sleeve at front, the force ot' said spring H being at` all times exerted to thrust thesleeve forward to compress the laterally-yielding locking devices into engagement with the grooved toolf shank, as clearly shown in Fig. 2. 'Y

When a tool has been inserted and locked in the socket, and it is desired to remove it,

the sleeve G is retracted against the force of' ICO IOC u rearl end ot1 the lever is raised, with an annu- 4 lar shoulder on the sleeve to retract the sleeve as the lip fi moves backward around the pivot of the lever.

The lever, when not raised to" manipulate ,the tool-locking devices, lies down about parallel with' the casing, (see Figs. l and 2,) so that its lip remains out of the way ofthe sleeve G, and does Vnot interfere with the turning movements ot' said sleeve with the spindlechuck when the tool is ai; work.

I have so organized the lever I, which actuates the tool-locking devices, that it is raised in a forward direction and moves the controlling-sleeve G backward to permit the toollocking devices to move laterally to release the tool, and this capacity of the lever to be lifted or rocked upward and forward to operrate the tool-locking devices is a very valua ble one in the manipulation of a dental-engine hand-piece, rendering its operation easy and rapid, enabling the thumb of thehand that holds the hand-piece to be used to work the lever with great ease, while the other hand is at the same time free to remove or insert the tool. The lever is also so organized as not to interi'ere with the ready" disconnection ot the liandlesection of the casing.

I disclaim herein the subject-matter claimed .IIO

in my aforesaid Letters Patent Nos. 233,708 and 233,709.

I claim herein as my invention@ l. The combination, substantially as hereinbeforc set forth, of the casing, the spindlechuck, the adjustable conc-collar constituting the pull journal or surface ot' the chuck, the cone-collar constituting the thrust journal or surface of said chuck, and the conical frictioncollar interposed between said thrust-collar and the casing to receive the thrust ofthe chuck. v

2. As a new article of manufacture, a friction-collar to receive the thrust of a lrevolving spindle, having a tapering external surface at one end and a tapering internal surface at the opposite end.

3. The hand-piece casing constructed, substantially as hereinbel'ore set forth, ot' three detachable tubular sections, in combination with a slide carried by one of said sections to prevent their accidental separation, While adjustable to permit the sections to be readily disconnected.

4. The combination, substantially as herein before set forth, of the casing, the spindlechuck, the three lug-ended tool-locking springs' arranged at substantially equal distances apart around said chuck, so as to act upon the inclined Wall of the locking-groove of a tool'- 3Q cess therein for the engagement of the vtool- 4o locking devices; second, a tapering surface in rear of said groove or recess to t a corresponding seat in a chuck-socket; and, third, a flattened or beveled driving-surface to en gage the driving-surface of the chuck-socket. 4 5

ln testimony whereof I have hereunto subscribed my name.

ELI T. STARR.

Witnesses WM. J. PEYTON, NELLIE HOLMES. 

